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(No Model.)

J.. S. ROSS. Electric Switch Board.

No. 229,757. Patented July 6,1880.

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EEEEE UNITED STATES PATENT OFFICE.

JAMES S. ROSS, OF NASHVILLE, TENNESSEE, ASSIGNOR TO THE NATIONAL BELL TELEPHONE COMPANY.

ELECTRIC SWITCH-BOARD.

SPECIFICATION forming part of Letters Patent No. 229,757, dated July 6, 1880.

Application filed May 17, 1880.

To all whom it may concern:

Be it known that I, JAMES S. Ross, of Nashville, county of Davidson, State of Tennessee, have invented an Improvement in Electric 5 Switch-Boards, of which the following description, in connection with the accompanying drawings, is a specification.

My invention relates to electric switchboards, and has for its object to simplify and I cheapen the construction thereof.

The .invention is shown embodied in a central-office switch-board of a telephonic exchange system; but it is obvious that it is equally applicable to any electric switch-board,

I as, for instance, those used for telegraphic purposes. In any case the object of a switchboard is to enable any one of a series of circuits tobe connected with any other of the said series, or with a ground-wire or battery or instrument, as desired. This is accomplished by having a series of independent electric conductors crossing but insulated from I another series, so that each conductor of either series crosses all those of the other series, and

may consequently be connected with any desired one of the other series by interposing a suitable piece of conducting material or connector between them.

It is obvious that if circuit-wires are con- 3 nected with each series any circuit-wire of one series may be directly connected with one of the other series, or, as in the arrangement common in telephone systems, two of one series to which the line-wires are connected are 3 5 each connected with the same one of the other series, which thus acts merely as a medium for connecting any two of the same series, and consequently any two of the telephonic circuits centering in the said office and switch- 4 board. As usually arranged for telephonic exchanges, one series of conductors is vertical and the other horizontal, and the vertical ones are connected with the different telephonic circuits, while the horizontal ones are used to form the connection between any two vertical ones and circuits.

In the construction of switch-boards the different conductors have usually been plates or strips of brass carefully bored to receive plug- 5 connectors and attached to wood-work, which (No model.)

has to be carefully made to prevent damage to the metal work from warping and shrinking; or, as commonly used for telephonic exchange, a series of vertical bars cross a series of horizontal bars, and may be connected therewith by springplugs of peculiar and expensive construction. In either case the switchboard, with its metal work, is an expensive structure, requiring a large amount of mate rial and careful workmanship in its construction, the metal conductors or plates, rods, &c., being made rigid, to allow the connector or -plug to be inserted between them with sufficient pressure to form a good electrical con tact, which could not be done with the usual flexible wire conductors if merely stretched across or fastened to the surface of the board.

My invention consists in providing a board or plate of insulating material with a series of holes, and in passing along the inside of said 0 holes flexible electric conductors, which maybe ordinary copper or iron wire, each of the said conductors passing continuously from one hole to another of a series or row of holes, and passing through and along the side of each hole 7 in the series.

The holes being arranged in vertical and horizontal rows, and a series of conductors or wires being entwined or laced through the vertical rows and another seriesthrough the hori- 8o zontal rows, the metal plug inserted in any of the holes will connect the two said wires, as desired, the said wires being supported by the solid part of the board around the holes, to enable them to afl'ord sufficient pressure against the plug.

The difi'erent wires are so entwined that on 7 one (as the front) face of the board they only pass across the shortest distance between the alternate pairs of holes in arow, they forming a loop over the part of the board between the said holes, the two parts of the said loop crossing one another on the other or rear face of the board, and the vertical wires thus pass through along the top and bottom sides of the 5 holes alternately, while the horizontal wires pass through along the right and left sides alternately. By this arrangement the horizon tal and vertical wires pass through each hole .at about one-fourth the periphery of the said hole from one another, and the holes being circular, the plug is forced into close contact with both of the said wires, which are pressed between the said plug and the board surrounding the hole. Thedifferent wires thus cannot come in contact with one another on the front face of the board, nor within the holes, but on the rear face of the board the directions of the two series cross, and, as herein shown, they are kept from contact by embedding or sinking the wires of one series in the board, so that those of the other series on the surface of the board cross in another plane at a distance from the embedded series.

Figure 1 is a front elevation of a switchboard embodying my invention; Fig. 2, avertical section thereof on line 00a; through a vertical line of holes; Fig. 3, a horizontal section thereof on line y 3 Fig. 4, a rear view of a portion thereof, and Fig. 5 a side view of the connecti ng-plu g detached.

The board a, of wood or other suitableinsulating material, and shown as faced with hard rubber, is provided with holes 1), arranged in vertical and horizontal rows, and with binding-screws 2, 3, 4, 850., one corresponding to each vertical row of holes. Connected with each of the said screws is a flexible conductor, (shown as a copper wire,) which is entwined in or looped through the corresponding vertical row of holes, as shown by the wire Sin Fig. 2, the said wire passing down the back of the board to the second hole from the top, then through the said hole, passing along the upper part thereof to the front of the board a, and up the front to the top hole, and through that, passing along the bottom to the back of the board, and then down the latter to the third hole below, and through this and to and through the one above it, in a similar manner to that in which it passed through the top pair of holes.

It will be seen that the wire 8 thus forms a series of loops around the space between the alternate pairs of holes in the row and passes through all of the said holes either along the top or bottom thereof.

Similar wires 0; are passed through all the vertical rows of holes, and wires h are looped in a precisely similar manner through the horizontal rows, as clearly shown in Figs. 3 and 4:; but in order to prevent these from touching the vertical wires where they cross on the back, as shown in Fig. 4, these wires are embedded in grooves 9, so that they pass along the back of the board to, out of reach of the vertical wires which pass over the surface, as clearly shown in Figs. 2, 3, and 4.

By inserting the plug 19 (shown as somewhat tapering) in one of the holes it will press and rub against the vertical wire passing through the top or bottom of the said hole and the horizontal wire passing through one side thereof, and will electrically connect them, and by placing two plugs in the same horizontal row the two circuits corresponding to the vertical rows in which the said plugs are situated will be connected by the horizontal conductor in the usual manner.

If desired, the wire may be wholly embedded in the board, or a facing placed thereon to cover the wire, either on the front or back thereof, so indicated by the dotted lines, Fig. 2, and the wires may be insulated from one another by any suitable insulating material, which should be removed from the portion passing through the holes.

The holes may be countersunk on the face of the board to facilitate the insertion of the plugs, and by placing the wires at a distance from one another of about one-fourth the'periphery of the hole the plug is forced into close contact with both of them.

Instead of looping a single continuous wire through a row of holes, as shown, separate conductors of any desired form can be passed through the holes and connected by a wire or other suitable conductor, the essential feature of my invention being that the solid portion of the insulating material forms a support for the conducting material passing through holes therein, so that cheap conducting material can be used instead of the rigid expensive bars and plates heretofore employed in switchboards.

The binding-screws s at the ends of the switch-board are to connect the horizontal conductors with similar series on other similar switch-boards in the usual manner, the several boards then forming the portions or sections of a single central switching or circuit-connecting device.

The vertical lines may terminate, in accordance with the usual arrangement, in the lower horizontal rows of holes, in which the plugs will remain inserted when the circuits are not in use for talking, the said circuits being then connected by the plugs with continuations thereof leading through indicating instruments or a central telephone.

I claiin 1. A switch-board provided with holes, combined with an electric conductor extended into the said holes at the sides thereof, and made to form ametallic connection between two or more holes of the said switch-board, whereby when a conducting-plug is inserted in one of the said holes it will be placed in complete electric connection with the conductor within the said hole of the switch-board, substantially as described.

2. An electric switch-board composed of a sheet or plate of rigid material provided with holes, and an electric conductor passed through the said holes and supported therein by-the rigid material, whereby, when a connector or plug of conducting material is inserted in the said holes against the conductor therein, the said plug is brought by its pressure against the conductors so supported in the said holes between it and the said rigid material into complete electric connection with the conductor, as set forth.

. 3. A non-conducting switch-board provided with intersecting rows of holes, combined with flexible electric conductors passed through the said holes and supported against the substantially-rigid insulating material, the conductors extending through all the holes of each row being electrically connected, whereby by inserting a plug of conducting material in one of the holes it will electrically connect the conductors of the two rows intersecting in the said hole, substantially as described.

4. In an electric switch-board, a sheet or plate of insulating material provided with holes arranged in intersecting rows, combined with continuous electric conductors, each entwined in or laced through a row of holes, passing through all of the holes in the said row, and resting against the material in which the holes are formed, the conductors of one series of rows being insulated from those of the intersecting series, thus enabling a conductor of one series to be connected with one of the other series by inserting a plug in the hole at which the rows containing the two conductors to be connected intersect, substantially as described.

5. In an electric switch-board, a board or plate of insulating material provided with intersecting series of rows of holes, combined with flexible electric conductors, each laced or entwined through all the holes of one row, the conductors of one series being sunk in a groove in the board to prevent them from coming in contact with the conductors in the other series at the points where their directions cross one another, substantially as described.

6. In an electric switch-board, a board or plate of insulating material provided with holes arranged in a row, combined with a flexible conductor laced or entwined in the said holes, substantially as described, passing through each of the said holes and forming a Y when a plug is inserted therein, it is wedged into close contact with the said conductors, substantially as described.

In testimony whereof I have signed my name 5 5 to this specification in the presence of two subscribing witnesses.

JAS. S. BOSS.

Witnesses:

H. 0. Ross, J NO. WATKINS. 

